Abstract: To allow a reflex sight to be mounted to the slider of a handgun and removed without the need for tools, an adapter shoe may be secured to the slider to provide an interface between an optics-ready recess of the slider and a mounting element that forms part of the reflex sight assembly. The adapter shoe may provide a dovetail track that engages complementary dovetail features of the mounting element. A push button retention mechanism may be biased to lock the mounting element within the adapter shoe. Actuation of the push buttons may retract the retention mechanism and allow the reflex sight assembly to slide out of the dovetail track.